"The Prophet (ﷺ) was met by some affair that made him happy, so he prostrated to Allah."

This Hadith is Hasan Gharib, we do not know of it except from this route, as a narration of Bakkar bin 'Abdul-'Aziz.

This is acted upon according to most of the people of knowledge, they held the view that one could perform the prostration of gratitude. And Bakkar bin 'Adbul-'Aziz bin Abi Bakrah is Muqarib (average) in Hadith.
Jami` at-Tirmidhi Book 21, Hadith 39
← Previous Hadith That he gave the Prophet (ﷺ) a gift or a camel, so the Prophet (ﷺ) said: "Have you accepted Islam?" He said: "No." He said: "Then I have been prohibited from the Zabd (gift) of the idolaters."

This Hadith is Hasan Sahih. And the meaning of his saying: "I haven been prohibited from the Zabd (gifts) of the idolaters" is their gifts.

It has been reported about the Messenger (ﷺ) that he used to accept the gifts of the idolaters while a dislike for that is mentioned in this Hadith.

And the implication is that this was after he used to accept from them, and then he later forbade their gifts.

Jami` at-Tirmidhi Book 21, Hadith 38 Next Hadith → That the Prophet (ﷺ) said: "Indeed a woman grants (assurances of protection) to a people" - meaning it is to be honored - "from the Muslims."

There is something on this topic from Umm Hani, and this Hadith is Hasan Gharib.

I asked Muhammad and he said: "This Hadith is Sahih. Kathir bin Ziad heard from Al-Walid bin Rabah, and Al-Walid bin Rabah heard from Abu Hurairah, and he is Muqarib (average) in Hadith.

Jami` at-Tirmidhi Book 21, Hadith 40